Control apparatus



March 3, 1942. H. A. ROL'NICK 2,274,741

CONTROL APPARATUS Filed Feb. 1, 1958 2 6" 0 f g 4' P 5 pa 6 6 B.INVENTOR HARRY A. ROLNlCK I swi ATTORNEY v pressure Patented Mar. 3,'1942 V r 2,274,741 I 7 CONTROL APPARATUS a 2,274,741 UNITED STATESPATENTIV'OFFICE,

, IlarryA, Rolnick, Philadelphia, Pa., assignor to i The BrownInstrument Company, Philadelphia,

Pa., a corporation of Pennsylvania 6 Claims The general object of thepresent invention is to provide improved control apparatus of thesocalled air controller type, adapted to effect a control actionautomatically dependent upon a variable control quantity, by varying acontrol in predetermined accordance with changes in the controlquantity. 1A more, specific object of the invention is to provide suchcontrol apparatus with improved means through which an initial fluidpressure change, resulting directly from a change in the controlquantity, efiects an automatic adjustment of the control apparatus andthereby produces another and related change in the control pressure. 7

A still more specific object of the present invention is to retaincertain characteristic advantages of, and to obtain certain advantagesnot obtainable with, air controllers of a type and form now in extensivecommercial use, comprising a so-called flapper valve, adjusted in directresponse to a change in a control temperature, pessure or other controlquantity, tovariably throttle the discharge through a bleed nozzle, andthereby vary the pressure in saidnczzle, and comprising means throughwhich said change in the nozzle pressure results in an immediate orquickly effected second adjustment of the flapper valve partiallyneutralizing the first mentioned vary the fuel supply rate in.accordance with through a pipe A., at a rate regulated bya-fluidpressure motor valve A which is" adjusted to changes in a fluidcontrol-pressure, the latter being transmitted to they motor pressurechamture to which a fluid pressure thermometerbulb adjustment thereof,and a slowly eifected'third adjustment of the flapper valve in thesame'direction as the original adjustment. Said second adjustment or itseffect is commonly referred to as a follow-up adjustment or eifect, andsaideffects by flapper valve adjustments. -My im-v proved air ccntrollerpreferably includes means for effecting follow-up adjustments oftheflapper valve, which are mechanically separate and distinct from themeans provided to secure the reset or compensating effects-,and whichmay be or. reset adjustment or omitted from themcntroller without,requiring any modification in the construction of, or interfering withthe operative effect -of the last mentioned means. 7 r

The various features of novelty which characterize my invention arepointed out with particularity in the claims, annexed to and forming apart of this specification. For a better understanding of the invention,however, its advantages and specific objects attained with its use,reference should be had to the accompanying ber A of the valve A andbeing varied automatically by variations in the furnace temperabisexposed. ..In the particular arrangement shown and hereinafterdescribed in detail, an increase or decrease in the temperature of thebulb Y results in an increase or decrease, respectivly, in the pressuretransmitted to the valve chamber A and in a decrease Lorincrease,respectively, I

in the rate at which fuel is supplied to the furnace.

Bourdon tube helix B, and a shaftB' given a clockwise orcounterclockwise adjustment by an increase or decrease, respectively, inthe pressure transmitted from the bulb b. to the helix B. The shaft Bcarries a pen arm 3?, adapted to makea temperature record on'ascaled'record chart disc B The shaft B also carries an arm B? throughwhich the angular adjustment of the shaftfBl resultingfrom changes inthe temperature ofthe bulb b,, adjusts the control apparatus and there-,

by varies the control pressure in the chamber A ,The arm B operatesthrough alink B connecting said arm to one arm of a floating bell cranklever 0, having an adjustablefulcrum pivot.

C-', and the second arm ofwhich carries a pin C engaging .one side of aflapper valveD. The

latter has a pivotal support D, and is spring biased to turn toward acooperating bleed nozzle E, so that thefdischarge orifice in the latteris subjected to an increased or decreased throttling effect by amovement of the pin C to theright orto the left. 7 The fulcrum/pivot C'of the lever C, is carried by a lever F pivoted at F to a cham beredelement G. The latter is normally stationary, but as hereinafterdescribed, may be bodily adjustedfor a calibration purpose. The member Galso carries the nozzle E, and the pivotal supf port D for the flapperva'lve D. V

The element G encloses a pressure space G havinga flexible wall portion.The latter is in the form of a bellows H having one end closed by an endwall H movable relative to the member G, and having its other end openand rigidly connected to the member G. As shown, the bellows H issubjected internally to the pressure of the atmosphere, and externallyto the pressure in the chamber or space G so that an increase in thelast mentioned pressure causes the bellows to contract, until theincrease in the bellows contracting force is balanced by a. spring forcewhich opposes the contraction of the bellows and increases as the latteris contracted. As diagrammatically shown, said spring force is whollydue to the resiliency of the bellows. The movable end wall H of thebellows H, is connected by a link I-I extending axially through thebellows to the lever F at a point between the pivots C and F. ThebellowsI-I isa-follow-up device, operating as hereinafter described, inresponse to a pressure change inthe chamber G to efiect a follow-upadjustment of the flapper D which quickly follows and partiallyneutralizes each flapper adjustment efiected by angular adjustment ofthe lever C. j

The nozzle E is connected to a source of air under pressure, shown aspipe I, by a branch pipe I which includes a throttling or flow retheport'K, and decreasing the throttling effect on the port K each of thetwothrottling effect variations contributing to a resultant increase inthe pressure in the chamber K. As shown, the

' valve'member K is connected to and adjusted by a lever L, which has astationary fulcrum pivot L, and is biased by a spring L formovestricting device 1 the latter preferably including a needle valve oranalogous element I which may be manually adjusted to vary the flowrestricting efiect of the device 1 The pressure in the nozzle E and inthe portion of the piping connecting the latter to the outlet of thedevice 1 thus depends upon the throttling effect of the flapper valve D,and is increased or decreased has a definite length for each value ofits internal pressure.

The expansion or contraction of the bellows J in; response to anincrease or decrease in the nozzle pressure, effects an increase ordecrease, respectively, in the delivery pressure of a valve K. Thelatter, as shown, comprises an inlet chamber K connected to a source ofair under pressure which may be, and as shown is'the pipe I, and whichcommunicates through a port K with the delivery pressure chamber K ofthe valve. The chamber K bleeds air to the atmosphere at a ratedepending on the adjustment of the valve member K which is adapted onits adjustment to simultaneously exert an increased throttling efiect onone, and a decreased throttling effect on the other of the two ports Kand K The pressure in the chamber K is aptly termed the control valvepressure, because it is transmitted through piping K to the motorpressure chamber A of the valve A ,'to control the adjustment of thelatter. It is also transmitted through the piping K to the chamber G,whereby changes in said pressure produce the previously' mentionedfollow-up adjustment actions of the bellows H.

In the arrangement shown in Fig. 1, the elongatioriof the bellows J,resulting from an increase in the throttlingeffect of the flapper valveD, results in a down movement of the valve member K increasing thethrottling efiect on ment in the direction to move the valve member Kupward.

The elongation of the bellows J gives the lever L a counterclockwiseadjustment through adjustable thrust transmitting means shown ascompriisng parts M, N and J The part J is carried by the lever J andextends into engagement with the part N, which isan arm generallyparallel to the levers J and L, and the part M is a thrust pininterposed between the levers N and L. Advantageously,for a reasonhereinafter stated, the" part J is adapted to be adjustably clamped tothe lever J in difierent positions along the length of the latter. Thearm N is mounted on a pivot support N adjacent the end of the lever L towhich the .valve member K is connected, so that the pin M is locatedbetween the pivotal supports N and L forrthearrn N and lever L. Inconsequence the leverage with which the lever J acts on the valve memberK may be varied by adjusting the pin M longitudinally of the lever Land'arm N. To facilitate such adjustment, the pin M is carried by oneend of a link M which is pivotally connected at its other end to an armM pivoted to turn about a stationary shaft M and adapted to be held, asby friction, in any angular position into which it may be adjusted.

Mounted on the support J alongside the bellows J, is a second pressureresponsive device 0, which, as shown, is a bellows similar to thebellows J. The bellows O has one end fixed to the support J and has itsother end closed and movable, and pivotally connected to the second endof the lever J The control valve pressure is transmitted to the interiorof the bellows 0' from the piping K, through a pipe 0 including a flowrestricting device 0 preferably comprising a manually adjustable needlevalve or analogous adjustable throttling element 0 r The parts are shownin Fig. 1, in the relative positions which they assume for' someparticular stable operating condition, in :which the temperature of thebulb b remains constant at a predetermined normalvalue. 0n a-decrease inthe temperature of the bulb b, the parts B C ,-J and K are givenmovements in the direction of the arrows respectively adjacent thoseparts, and on an increase in the temperature of the bulb, the said partsare given movements in directions opposite those indicated by theadjacent arrows. The movement of the pin C in the direction of theadjacent arrow, occurring as a result of a decrease in the temperatureof the bulb b, moves the flapper D away from the nozzle E, and therebyimmediately reduces the pressure in the chamber of the bellows J, whichis in relatively free, or unrestricted, communication with the nozzle E,a

The resultant up adjustment of the valve member K increases thethrottling of the port K and reduces the throttling of the port K andeach of those throttling changes contributes to the resultant reductionin the control valve pressure in'the chamberK The reduction in thatpressure, transmitted by the piping K 'to the valve chamber A results inan opening adjustment of the valve A thereby increasing the fuel supplyto the furnace A, and tending to raise the furnace temperature towhich'thebulb' bresponds, to its normal value. The decrease in thecontrol valve pressure, transmitted by the piping K to the chamber G,results in an immediate elonand follow-up adjustments of the flappervalve.

D, resulting from the described decrease in temperature of the bulb b,is a reduction in the pressure in the bellows J and a correspondingreduction in thecontrol pressure maintained in the chambers K A and Gand piping K This reduction in the control pressure is transmitted tothe pressure responsive device at a slow rate, due to the eiTect of theflow restricting device O As the pressure in the bellowsO isthus'reduced, that bellows contracts, and the valve member K is given afurther adjustment in the same direction as that produced by theprevious contraction of the bellows J. o

. Operations which are the converse of thosejust described result froman increase in the temperature of the bulb b following a steadyoperating condition in which the control parts have come into acondition of equilibrium. As those'skilled in the art will understand,while the normal and ultimate average effect of an increase or decreasein the temperature of thebulb b is a corresponding quick adjustment ofthe control pressure in the corrective direction efiected by the changein length of the bellows J and adelayed adjustment of the controlpressure in the same directioneffected through the bellows O, withrelatively rapidly alternating increases and decreases int-hetemperature of the bulb, the bellows 0 may either slowly contract orslowly expand during a period immediately following either a contractionor an expansion of the bellows J. However, when the resultant of rapidlyrecurring bulb temperature fluctuations is an increase or decrease, theultimate resultant effect of the operation of the device O is to augmentthe effect on the control pressure produced by the ultimat resultanteffect of the bellows J. The bellows 0 thus serves the normal intendedpurpose of compensating adjustment means, in that it compensates forload changes in the controlled system. Thus in the furnace controlsystem shown in Fig. 1, the bellows ,0 causes the valve A to be morewidely open for a given bulb temperature, during any extended period ofoperation in whichthe furnace load is relatively heavy, and the need forfuel correspondingly large, than during anextended period in which thefurnace load is relatively light and less fuel is needed.

The. apparatus diagrammatically illustrated in Fig. 1 is characterizedby its relative simplicity and inherent operative reliability and by theease with which desirable adjustment may be provided. Thus, as shown, inFig.1, the relative effects of the pressure responsive-devices Jand O onthe adjustment of the valve member'K and on the control valve pressure,may be varied by adjusting the thrust part J 3 along the length of thelever J Furthermore, with any given adjustment of the part J thethrottling range of the control apparatus, or range of variation in theand arm N: An adjustment of the pin M-to the right increases, 'andits-adjustment'to the left control valve pressure produced by a givenchange in the pressure transmitted from the nozzle'E to thebellows J."

The type of apparatus-shown" in Fig; 1 is advantageously characterizedfurther, by-the flexinozzle" pressuretransmitted to the bellows Jdecreases the m'agnitudeof the change in the.

bility which it permits in the design and assembly 'ofapparatusoperating in accordance with the principles of the invention: Thus forexample, the size and inherent elasticity of each of'the bellows devicesJ and O employedfm'ay'be determined with specialreference to theparticular conditions ofuse, and inthe actual production of a commercialinstrument; the latter may be assembled for use under particularoperating conditionsj by suitable selection from stock inclu'd- Q inginterchangeably usable bellows 'parts'of dif ferentfdimensions andresiliency. Thev'alve K- '1 is adapted, desirablyincludes" means forvary 1 ing the control setting point, or'valu'e of the control quantitywhich the a'pparatus tends to maintain; One known arrangement for f thepurpose is illustrated in Fig. and comprises means for bodily adjustingthe member G- about a supporting pivot- G' so asto thereby change therelativepos'itions of the flapper D and nozzleE. with a given positionof the arm B adjustment, the'member G'is shown as formed with a gearsegment G engaged by a manually As shown,-the rotation of the worm Palso'angularly adjusts a gear segment Q pivoted at Q and connected by alink Q to an index Q pivoted on, or coaxially with, the shaft B',-andadapted to indicate'on the chart B the temperature of the bulb b In themodification shown in Fig. 2, the pipe 0' with its flow restrictingdevice 0 does not connect the bellows O to the pipe K, but to 1 contractand elongate, the bellows O corresponde ingly' elongates and contracts,respectively. The

arrangement-shown in Fig.2 has'the advantage over that shown in,Fig. 1in 'that it is practically possible to more readily a'nd'accuratelyregulate the flow through a restricted passage of a' liquid than of anelastic fluid as air.

To effect such rotatable worm P supported in the-bearings P.

which the apparatus tends to main- While in accordance with theprovisions of the statutes, I have illustrated and described the a bestform of embodiment ,of1my invention now knownto me, it will be apparentto those skilled in the art that changes may be made in the form of theapparatus disclosed without departing from the spirit of my invention asset forth in the appended claims and that in some cases certain featuresof my invention may be used to advantage without a corresponding use ofother features. Y

Having now described my invention, what I claim as new and desire tosecurev by Letters Patent, is: A 1 c 1. In .air control apparatus, thecombination with a pressure responsive device, of means,-comprising anadjustable valve mechanism and means responsive to variations in acontrol quantity for adjusting said valve mechanism, for subjecting saiddevice to a pressure varying promptly and in predetermined relation with-variations in said control quantity, means including a secondadjustable valve mechanism for maintaining a control pressure dependenton the adjustment of said second valve mechanism, a second means toadjust said first valvemechanism, a non-restricted flow passage. throughwhich changes in said controlled pressure operate said second adjustingmeans to adjust said first valve mechanism in a direction opposite tothe movement imparted to it by the control reisponsive means, a secondpressure responsive ldevice, means including a restricted flow passagethrough which changes in said control pressure are slowly transmitted tosaid second responsive device, and levermechanism separate from saidfirst mentioned valve mechanism actuated jointly by the two pressureresponsive devices to directly adjust said second valve mechanism inprompt response to a change in the pressure to which the first mentionedresponsive device is subjected, and to effect a retarded adjustment ofsaid second valve mechanism on a change in said control pressure inadirection augmenting control pressure.

3. Apparatus as specified in: claim 1,- including means for varying therelative adjustment effects of the two pressure responsive devices onsaid second valve mechanism, resulting from a change in the controlquantity.

4. Apparatus as specified in claim' 1, including means for ,varying themagnitude of the control pressure change produced by a given' change inthe pressure to which the first mentioned device of claim 1 issubjected.

5. In air control apparatus, the combination with a pressure responsivedevice, of means, comprising an adjustable valve mechanism and meansresponsive to variations in a control quantity for adjusting said valvemechanism, for subjecting said device .to a pressure varying promptlyand in predetermind relation with variations in said control quantity,means including a second adjustable valve mechanism'ior maintaining acontrol pressure dependent on the adjustmentiof said second valvemechanism, a" second means to adjust said first valve mechanism, anon-restricted flow passage through which changesin said controlpressure operate said second adjusting means to adjust said first valve,mechanism in a direction' opposit e to the movement imparted to it bythe .control responsive means, a second pressure responsive device,means including a, restricted 'fiow passage, through] whichchan'gesjinsaid'control pressure are slowly transmitted to said second responsivedevice, and means cooperating with the two pressure responsive devicesto adjust said second valve mechanism in prompt response to a change inpressure to whichthe first mentioned re-' sponsive device is subjected,and; to effect a retarded adjustment of "said second valve mechanism ona changein said control pressure in a direction augmenting the lastmentioned change, each of, the pressure responsive devices being an.expansible container subjected internally to the corresponding pressureand both containers acting on saidsecond valve mechacomprising anadjustable valvmechanism and means responsiveto variations in a controlquantity for adjusting said valvemechanism, for subjecting said deviceto a pressure varying promptly and in predetermined relation withvariations in said control quantity, means ineluding a secondadjustable-valve mechanism for maintaining a control pressuredependenton the adjustment of said second valve mechanism, a second. means toadjust said first valve mechanism, a non-restricted flow passage throughwhichchanges in said controlpressure operate said second, adjustingmeans to adjust said first valve mechanism in a direction opposite tothe movement imparted to it by the control responsive :means, a secondpressure responsive device, means including a restricted fiowpas sagethrough: which changes in said control pressure are slowly transmittedto said second responsive device, and means cooperating with the twopressure responsive devices to adjust said second valve mechanism inprompt response to a change in the pressure to which the first mentionedresponsive device is subjected, and to efiect'a retarded adjustmentofsaid second valve mechanism on a change in said control pressure in adirection augmenting the last mentioned change, each of the twopressureresponsive devices being bellows elements located alongside ofone another and each having one end stationary and tthe other endmovable and connected to the corresponding end of a floating lever.means operatively engaging said lever intermediatelits' ends throughwhich the expansion of either b llows produces an adjustment of thesecond valve mechanism in one direction. and contraction produces anadjustment on the opposite direction and in which the pressure first.mentioned is transmitted to the interior of oneflof said bellows .andthe control pressure is transmitted HARRY AgROLNICKr

